The quality of speech is inevitably degraded by environmental noise. In order to improve the quality of the speech, the environmental noise has to be reduced.
To reduce the environmental noise, a short-term spectral estimation algorithm is usually adopted. According to this algorithm, in the frequency domain, power spectrum of the speech is obtained according to the power spectrums of the noisy speech and the noise. Then amplitude spectrum of the speech is obtained according to the power spectrum of the speech. A time-domain speech is then obtained through an inverse Fourier transformation.